Uninterruptible power supply device with circuit for degradation judgment of storage battery

ABSTRACT

There is herein provided an uninterruptible power supply device with a degradation judgment circuit  4  of a storage battery  2  which can perform an exact judgment, continuing the power supply to a load apparatus  8  stably without giving the excessive burden to the storage battery  2 . The storage battery  2  is floatingly charged from a rectifier  1  connected with the power source  10 . The device has the control circuit  3  for controlling the output voltage of the rectifier  1  and the degradation judgment circuit  4 . The output voltage of the rectifier  1  is lowered to below a steady state by the control circuit  3 . As a result, the storage battery  2  discharges with the current Idc restricted rather than rated discharge current. And a part of power supply is supplied to the load  8 . The degradation judgment circuit  4  judges the degradation of the storage battery based on the discharge voltage Vdc.

BACKGROUND OF THE INVENTION

This invention relates to an uninterruptible power supply device ofcomputers or communication apparatuses, connecting to a circuit fordegradation judgment for a storage battery built therein.

Supplying a current from an alternating power to various communicationapparatuses and so on, the uninterruptible power supply device isinserted between the alternating power and such a communicationapparatus in order to prevent the power from stopping by its unexpectedfailure or an interception of a breaker and damaging the apparatus orinterrupting work.

There are two types of a normal converter power supply system and anormal supply system from a commercial power roughly dividing suchuninterruptible power supply devices. The former is equipped with arectification circuit, a storage battery and a converter. It normallycarries out floating charge to the storage battery with a direct currentobtained from the rectification circuit and supplying an alternatingcurrent converting from the direct current by the converter to the loadapparatus. In the latter, the alternating current is directly suppliedfrom an alternating power to the load apparatus. On the other hand, thestorage batter is carried out such floating charge with a direct currentof an alternating-direct current conversion from the power.

If any type of the uninterruptible power supply devices stop to besupplied power at power failure etc., the storage battery will dischargeand a direct-alternating current conversion of the discharge currentwill be carried out. And as long as the discharge of the storage batterycontinues, power is supplied and the load apparatus continues to drivewithout an intermission. If the power failure and so on stops in themeantime, it will return to the usual power supply state.

The storage battery degrades by over discharge of itself or drives ofitself for a long range time. If the storage battery of theuninterruptible power supply device has degraded, discharge will notcontinue for a long time and the power source will not return in time,or if the degradation is remarkable, the discharge voltage isinsufficient to drive the load apparatus.

Therefore, an uninterruptible power supply device attaches a circuit forjudging the degradation of the storage battery. It is most generallyknown such a circuit judges by comparing a curve of the instantdischarge current of the storage battery and a discharge curve of anormal storage battery i.e. reference curve thereof. It is also knownthat an impedance of such a storage battery is measured to judge thedegradation. Japanese Patent Provisional Publication No. 2000-50525discloses a method for judging the degradation by observing dischargeprogress of the storage battery when reducing a supplying voltage to theload from the power converter to make the storage battery discharge.

However, these prior judgment methods take a long time to make thestorage battery discharge until the curve of the discharge current isobtained enough. A reference curve according to a kind of a storagebattery or/and a discharging rate thereof is required and that a memoryfor the reference curve is required. A setup thus becomes complicated.Moreover, judging promotes the degradation of the storage battery sincean unusual burden is applied thereto. Actually, when the storage batteryhas degraded, the discharge may stop during the judgment, and anoriginal function may be unable to be achieved as an uninterruptiblepower source.

SUMMARY OF THE INVENTION

The present invention has been developed to solve the foregoingproblems. It is an object of the present invention to provide anuninterruptible power supply device for supplying power to a load andcharging floatingly to a storage battery with the degradation judgmentcircuit of the storage battery which can perform an exact judgment,achieving an original function as an uninterruptible power source ofcontinuing the power to stably supply to the load apparatus withoutgiving the excessive burden to the storage battery.

The present invention was developed for accomplishing the foregoingobject. The uninterruptible power supply device of the present inventionis used for supplying power to a load and charging floatingly to astorage battery from a converter connecting to a alternating currentpower source. The device comprises a control circuit for controlling anoutput voltage of the converter to lower below a steady state, thestorage battery thus to discharge at a more limited current than therated current thereof, and the converter to supply a part of loadcurrent to the load; and a judgment circuit for judging the degradationof the storage battery based on the discharge voltage of the limiteddischarge current.

In another aspect of the uninterruptible power supply device of thepresent invention comprises; a control circuit for controlling an outputvoltage of the converter to lower below a steady state, the storagebattery thus to discharge at a more limited current than the ratedcurrent thereof, and the converter to supply a part of load current tothe load; and a judgment circuit judges the degradation of the storagebattery based on a charging time of the storage battery from whencontrolling, by the control circuit, the converter to return the outputvoltage to the steady state until completing full charge state thereof.

In the uninterruptible power supply device of the present invention, theconverter is a rectifier and the load may include a direct-alternatingcurrent inverter in addition to a whole load apparatus.

In the present uninterruptible power supply device, the converter is arectifier and a direct-alternating current inverter may be connected onmidway between the storage battery and the load.

In the present uninterruptible power supply device, the convertercomprises a mutual transducer of direct and alternating current, whichconnects to the power source in parallel with the load, and whichconnects the storage battery thereto.

In the present uninterruptible power supply device, the convertercomprises a transducer of alternating and direct current which connectsto the power source in parallel with the load, and which connects thestorage battery and a direct-alternating current inverter.

In the present uninterruptible power supply device, the limiteddischarge current of the storage battery, by controlling the outputvoltage of the converter to lower below the steady state, is almostconstant what is equivalent to 10-50% of the maximum current of theload. In an embodiment, the limited discharge current of the storagebattery is controlled at a constant current of around 30% of the maximumcurrent of the load.

In the present uninterruptible power supply device, the control circuitconnects to a trigger signal source which comprises memory memorized anoperational schedule of the degradation judgment, and the converterstarts to lower the output voltage at the timing of the trigger signaland the storage battery then starts to discharge.

In the present uninterruptible power supply device, the converter andthe control circuit comprise a rectifier for obtaining a direct currentfrom the alternating current power source, and a closing loop forbringing the voltage of the direct current close to an appointed directcurrent voltage with a pulse duration modulation control for analternating input voltage of itself.

In the present uninterruptible power supply device, the degradationjudgment circuit comprises a comparator for comparing between anappointed value of a direct current voltage from the control circuit andthe discharge voltage of the storage battery.

In the present uninterruptible power supply device, the degradationjudgment circuit comprises an integration circuit for integrating with avoltage difference between the appointed value of the direct currentvoltage form the control circuit and a discharge voltage of the storagebattery, and a comparator for comparing between the output voltage ofthe integration circuit and a standard voltage.

In the other aspect of the uninterruptible power supply device of thepresent invention, the degradation judgment circuit comprises a timerfor measuring the charge time of the storage battery.

In the other aspect of the present uninterruptible power supply device,the degradation judgment circuit comprises a timer connecting to acomparator for comparing a charging current of the storage battery witha base current.

BRIEF EXPLANATION OF DRAWINGS

FIG. 1 is a block circuit diagram showing an example of composition ofthe uninterruptible power supply device with the degradation judgmentcircuit of the storage battery which applies the present invention.

FIG. 2 is a block circuit diagram showing an example of the controlcircuit of the uninterruptible power supply device with the degradationjudgment circuit of the storage battery which applies the presentinvention.

FIG. 3 is a waveform diagram explaining a circuit operation of theuninterruptible power supply device with the degradation judgmentcircuit of the storage battery which applies the present invention.

FIG. 4 is a block circuit diagram showing another example of thecomposition of the uninterruptible power supply device with thedegradation judgment circuit of the storage battery which applies thepresent invention.

FIG. 5 is also a block circuit diagram showing another example of thecomposition of the uninterruptible power supply device with thedegradation judgment circuit of the storage battery which applies thepresent invention.

FIG. 6 is a block circuit diagram showing an example of degradationjudgment circuit of the storage battery of the uninterruptible powersupply device with the degradation judgment circuit of the storagebattery which applies the present invention.

FIG. 7 is similarly a block circuit diagram showing another example ofdegradation judgment circuit of the storage battery.

FIG. 8 is similarly a block circuit diagram showing another example ofdegradation judgment circuit of storage battery.

DETAILED DESCRIPTION OF THE INVENTION

Preferable examples of the present invention will be below explained indetail seeing drawings.

FIG. 1 shows a block circuit diagram of an example of theuninterruptible power supply device with the degradation judgmentcircuit of the storage battery, which applies the present invention, isso called as a normal inverter power supply system.

In the uninterruptible power supply device of FIG. 1, a rectifier 1 isconnected to a power source of commercial alternating current 10, and astorage battery 2 and a load apparatus 8 through an inverter 6 areconnected to the output side thereof. A control circuit 3 is connectedto the rectifier 1, refer FIGS. 1 and also 2, of which direct currentoutput is controlled in an optional constant voltage. A degradationjudgment circuit 4 for battery based on discharge voltage of the storagebattery is connected to the control circuit 3 with a trigger signal forstarting operation thereof.

The rectifier 1, in FIG. 2, to which the control circuit is connectedfor obtaining output of a direct current voltage Vdc from the powersource of the commercial alternating current 10 aiming at an appointedvalue Vdc* of a direct current voltage. From the appointed value Vdc* ofthe direct current voltage, a voltage comparator 23, PID control device24, that is a Proportional-Integral-Derivative control, and a pulsewidth modulation (PWM) 25 are connected in this order, and then thedirect current voltage Vdc is output. The direct current voltage Vdcfeeds back to the voltage comparator 23 and thus constitutes a closingloop.

The uninterruptible power supply device of FIG. 1 converts alternatingcurrent from the commercial power source to a constant voltage directcurrent wit the rectifier 1 and the control circuit 3 under the steadystate. The input alternating current is controlled with the pulse widthmodulation and repeatedly controlled with the closing loop to approachthe appointed value Vdc* of the direct current voltage which is set upin the control circuit 3, and which is then output under the steadystate. The direct current output carries out the floating charge of thestorage battery 2, changes to a sine wave voltage, that is analternating current, with the inverter 6, and then the changedalternating current is supplied to the load apparatus 8.

When power stops from the power source of commercial alternating current10 at a power failure and so on, the storage battery 2 discharges andits discharge current is changed into alternating current with inverter6. The load apparatus 8 continue to be supplied of power and operatewithout an intermission as long as continuing of discharge from thestorage battery 2. If the power failure and so on stops in the meantime,it will return to the usual power supply of the steady state.

In order to judge the degradation of the storage battery 2, theappointed value Vdc* of the direct current voltage of the controlcircuit 3 is lowered and then the output voltage of the rectifier 1 islowered to below the steady state at the time of inputting of thetrigger signal to the control circuit 3. In this example, thedegradation is judged by setting up the appointed value Vdc* of thedirect current voltage so that the storage battery 2 discharges thecurrent equivalent to 30% of the maximum current of the load apparatus8.

In the storage battery 2 of this example, 168 storage cells of ratedvoltage 2V per one connects in series to each other so that the ratedvoltage thereof is 336 V. The appointed value Vdc* of the direct currentvoltage set in the control circuit 3 under the steady state is 382 V offloating charge voltage, namely 2.275 V per a cell. The output voltageof the rectifier 1 is controlled to 382V by the closing loop function ofthe control circuit 3 under the steady state. When the trigger signalinputs in the control circuit 3, the appointed value Vdc* of the directcurrent voltage is set to 340V, namely 2.024 V per a cell, and thedegradation is judged by operating the closing loop function of thecontrol circuit 3. Consequently, 30% of discharge current Idc of thestorage battery 2 and 70% of current from the rectifier 1 inputs intothe inverter 6 if the load apparatus 8 is operating with the greatestcurrent. The control circuit 3 keeps the appointed value Vdc* of thedirect current voltage constant. If an actuating current of the loadapparatus 8 decreases from the maximum, the discharge current Idc of thestorage battery 2 will be kept constant and the current from therectifier 1 will decrease. Therefore, if the actuating current of theload apparatus 8 is 50% of the maximum, 30% of the discharge current Idcof the storage battery 2 and 20% of the current from the rectifier 1 areinput. That is to say, if the discharge current of the storage batteryis set to 30%, the examination can start when the rate of load is over30%.

FIG. 3 shows the waveform of the actuating current when judging thedegradation of the present uninterruptible power supply device with thedegradation judgment circuit of the storage battery and when before andafter the judgment. The input current Iin from the power source ofcommercial alternating current 10 controlled to the sign wave start tothe degradation judgment with a trigger signal, see (A), the amplitudedecreases maintaining the sine wave since, see (C), the dischargecurrent of the storage battery is added. As the current Idc from thestorage battery 2 is added to the output current of the rectifier 1, itis constant that the whole current flows into the inverter 6. Therefore,see (D), the output alternating current lout from inverter 6, that isthe current supplied to the load apparatus 8, is constant. Even if thedegradation judgment is carried out, the load apparatus 8 can continueoperation similar to the steady state.

FIG. 3(B) shows the rated voltage, an appointed value Vdc* of the directcurrent voltage, and discharge voltages of the storage battery 2. Asshown in (B), a potential difference ΔVdc1 between a discharge voltageVdc1 and the appointed voltage Vdc* is large if the storage battery 2 isnormal. A potential difference ΔVdc2 between a discharge voltage Vdc2and the appointed voltage Vdc* is small if the storage battery 2 hasdegraded. In the degradation judgment circuit 4 for the storage batteryby the discharge, normal or degradation of the storage battery 2 isdistinguished strengths of the discharge voltages ΔVdc in the state tobe judged, refer FIGS. 6 and 7.

For example, when a appointed value Vdc* of the direct current voltageis lowered to 340V in degradation judgment state, a discharge voltage ofnew storage battery 2 is 346V but a discharge voltage of a storagebattery degraded in about 50% is 342V. The degradation can be judged bysuch distinction of the strength of the discharge voltage.

After time T have passed, returning the set of the appointed voltageVdc* of the control circuit 3 to 382V of the steady state from 340V ofthe degradation judgment state, the output voltage Vdc of the rectifier1 builds up gradually to 382V with the closing loop function of thecontrol circuit 3, restricting the charge current to the storagebattery. Therefore, as shown in FIG. 3(C), the storage battery 2discharged as current Idc until that moment turns to be charged from therectifier 1. That means that the current Idc of the storage battery 2changes the charge current indicated the negative side from thedischarge current indicated the positive side. The storage battery 2 isthen saturated with the charge by passing time t.

FIG. 4 is the block circuit diagram showing another example of acomposition of the present uninterruptible power supply device with thedegradation judgment circuit of the storage battery. The uninterruptiblepower supply device is a normal supply system from a commercial power.

As shown in FIG. 4, a load apparatus 8 is connected to the power sourceof commercial alternating current 10 through a switching circuit 9. Aconverter 12 as for converting mutually alternating-direct current ordirect-alternating current is also connected thereto in parallel withthe load apparatus 8. The control circuit 3 is connected to theconverter 12, and the storage battery 2 is also connected to theconverter 12. An ammeter 7 is connected to the output side of thestorage battery 2 and also to the degradation judgment circuit 5 for thestorage battery 2 by the charge time thereof. A trigger signal of thedegradation judgment 5 can input to the control circuit 3 and thedegradation judgment circuit 5. The control circuit 3 is the samecomposition as what is shown in FIG. 2.

In the uninterruptible power supply device, the switching circuit 9turns on under the steady state and, thus, power is directly supplied tothe load apparatus 8 from the power source of commercial alternatingcurrent 10. On the other hand, the converter 12 convertsalternating-direct current to floating the storage battery 2. If thepower from the power source of commercial alternating current 10 stopsby the power failure and so on, the switching circuit 9 operates toswitch off. Then the storage battery 2 discharges and the converter 12converts direct-alternating current from its discharge current. The loadapparatus 8 continue to be supplied of power and operate without anintermission as long as continuing of discharge from the storage battery2. If the power failure and so on stops in the meantime, the switchingcircuit 9 switches on and it return to the usual power supply from thepower source of commercial alternating current.

The degradation judgment operation and the time chart of the controlcircuit 3 of the uninterruptible power supply device shown in FIG. 4 isthe same as that of FIG. 1 so that such explanation is omitted foravoiding duplicate description. However, the circuit operation differs alittle at a point of the degradation judgment circuit 5 bases on thecharge time of the storage battery.

As shown in FIG. 3(C), after ending the discharge with the restrictedcurrent restricted for the degradation judgment of the storage battery,that means the time T passes, if the storage battery 2 is normal, thecharge continues for a long time as seen t2, but if the storage battery2 is degraded, the charge completes for a short time as seen t1.Therefore, the normality or the degradation of the storage battery isdistinguished by measuring the time t with a timer in the degradationjudgment circuit 5.

For example, when an appointed value Vdc* of a direct current voltage islowered to 340V and a discharge time T takes 15 seconds, a charge time tof a new storage battery 2 is 12 seconds, but a charge time t of astorage battery 2 degraded about 50% of its capacity is 4 seconds. Thedegradation is thus judged by measuring the charge time t.

FIG. 5 is also a block circuit diagram showing another example of thecomposition of the uninterruptible power supply device with thedegradation judgment circuit of the storage battery which applies thepresent invention. This type of the uninterruptible power supply deviceis a normal supply system from a commercial power and, however, isdifferent in aspect of the device from the above one.

As shown in FIG. 5, the load apparatus 8 through the switching circuit 9is connected to the power source of commercial alternating current 10.The rectifier 1 as the transducer and the inverter 6 are also connectedthereto. The output side of the inverter 6 is connected to the loadapparatus 8. The control circuit 3 is connected to the rectifier 1. Thedegradation judgment circuit 4 of the storage battery based on thedischarge voltage of the storage battery is connected to the controlcircuit 3. The storage battery 2 is connected between the rectifier 1and the inverter 6. Moreover, the schedule timer 14 which generates thetrigger signal for the degradation judgment of the storage battery isalso connected to the control circuit 3. The control circuit 3 is thesame composition as what is shown in FIG. 2.

In the present uninterruptible power supply device, the switchingcircuit 9 is turned on under the steady state, so the power is directlysupplied to the load apparatus 8 from the power source of commercialalternating current 10. On the other hand, the floating charge iscarried out to the storage battery 2 by the direct current from therectifier 1. The switching circuit 9 operates if the power from thepower source of commercial alternating current 10 stops by the powerfailure and so on. Then the storage battery 2 discharge anddirect-alternating current conversion of its discharge current arecarried out at the inverter 6. The converted alternating current issupplied to the load apparatus 8. If the power failure and so on stopsin the meantime, the switching circuit 9 switches on to return to theusual power supply from the power source of commercial alternatingcurrent.

The explanation of operation containing the circuit of the controlcircuit 3 and the time chart in the degradation judgment operation ofthe uninterruptible power supply device with the degradation judgmentcircuit of the storage battery shown in FIG. 5 is the same as that ofFIG. 1. But the degradation judgment of the storage battery isperiodically started based on the trigger signal which is generated bythe schedule timer 14 according to the maintenance cycle of theapparatus.

FIG. 6 is the circuit diagram showing a concrete example of compositionof the degradation judgment circuit 4 of the storage battery shown inFIG. 1 and FIG. 5. This type of a degradation judgment circuit 4 of thestorage battery is based on discharge voltage of the storage battery 2,and has a direct current power source 16 and a voltage comparator 18. Asshown in FIG. 3(B), a voltage ΔVdc, that is a potential differencebetween the discharge voltage Vdc of the storage battery 2 and theappointed value Vdc* of the direct current voltage at the time of thedegradation judgment of the storage battery, is large if the storagebattery 2 is normal, but is small if the storage battery 2 has degraded.The voltage ΔVdc and a voltage of the power source 16 is compared by thevoltage comparator 18. Then a normal signal is obtained from the voltagecomparator 18 if the former one is larger, or else a degradation signalis obtained.

FIG. 7 is also the circuit diagram showing another example ofcomposition of the degradation judgment circuit 4 of the storage batterybased on the discharge voltage of the storage battery shown in FIG. 1and FIG. 5. This type of a degradation judgment circuit 4 of the storagebattery, the degradation is also judged based on the potentialdifference ΔVdc. The value of the voltage ΔVdc of the potentialdifference is so small that it is difficult to handle. Therefore, thevoltage ΔVdc of the potential difference is integrated with time T atthe integrator 15 and then the integrated value of the voltage ΔVdc andthe voltage of the power source of base voltage 17 is compared by thevoltage comparator 19.

The degradation judgement circuit based on the discharge voltage of thestorage battery 2 shown in FIG. 6 and FIG. 7 can be applied to theuninterruptible power supply device shown in FIG. 4 as well as the oneshown in FIG. 1 and FIG. 5.

The degradation judgment circuit 5 of the storage battery shown in FIG.4 is on the charge time and is fundamentally composed of the timer. Aconcrete example of the degradation judgment circuit 5 of this type canalso be used as shown in FIG. 8. The circuit 5 has a power source 20 ofa base current, a current value comparator 21 and a timer 22. The chargecurrent Idc of the storage battery 2 and a current from the power source20 is compared by the current value comparator 21 and time is measuredby the timer 22 while the charge current Idc is larger than the currentof the power source 20. The normal signal is given if the measured timeis long, or else a degradation signal is given.

The degradation judgment circuit based on charge time can be applied tothe uninterruptible power supply device shown in FIG. 1 and FIG. 5 aswell as that shown in FIG. 4.

Furthermore, both degradation judgment circuits 4 of the storage batterybased on the discharge voltage and on charge time can also be applied tothe uninterruptible power supply device which supplies the directcurrent. In the uninterruptible power supply device, the inverter 6 andthe load apparatus 8 are collectively considered as the load 11 in thecircuit shown in FIG. 1.

The schedule timer 14, which generates the trigger signal for thedegradation judgment of the storage battery shown in FIG. 5, is appliedto the uninterruptible power supply device shown in FIG. 1 and FIG. 4.

As a whole, illustrated or described circuits or elements can be carriedout in all combination within a range of the essence of the presentinvention.

As it is mentioned above in detail, the judgment of the storage batteryby the present uninterruptible power supply device with the degradationjudgment circuit of the storage battery can judge exactly in short timewithout the unnecessary burden to the storage battery since the storagebattery is not made to discharge with a long time or large current. Theuninterruptible power supply device does not lead to so-calleddestructive inspection. The present uninterruptible power supply devicecan judge exactly and supplies stably source to load so that is verypreferable to automatically and intentionally maintain a storage batterywithout stopping the load apparatus.

1. An uninterruptible power supply device for supplying power to a loadand for floatingly charging a storage battery from a converterconnecting to an alternating current power source, and having adegradation judgment circuit for the storage battery, the degradationjudgment circuit comprising: a control circuit for controlling an outputvoltage of the converter to be lower than a steady state voltage, so asto cause the storage battery to discharge at a more limited current thanthe rated current of the storage battery, and so as to cause theconverter to supply a part of a load current to the load; a judgmentcircuit that judges the degradation of the storage battery based on acharging time of the storage battery from a time when the controlcircuit controls the output voltage of the converter to return to thesteady state voltage to a time when the battery is fully charged, thejudgment circuit using the charging time to determine whether thestorage battery is degraded or normal, a degraded storage battery havinga maximum storage capacity that is less than a maximum storage capacityof a new storage battery of the same kind thereof, and a timer formeasuring the charging time of the storage battery from the time whenthe control circuit controls the output voltage of the converter toreturn to the steady state voltage to the time when the battery is fullycharged.
 2. The uninterruptible power supply device according to claim1, wherein said judgment circuit comprises a timer connecting to acomparator for comparing a charging current of the storage battery witha base current.
 3. The uninterruptible power supply device according toclaim 1, wherein said converter is a rectifier and said load includes adirect-alternating current inverter and a load apparatus.
 4. Theuninterruptible power supply device according to claim 1, wherein saidconverter is a rectifier, the uninterruptible power supply devicefurther comprising a direct-alternating current inverter connectedmidway between the storage battery and the load.
 5. The uninterruptiblepower supply device according to claim 1, wherein said convertercomprises a mutual transducer of direct and alternating current, whichconnects to the power source in parallel with the load, and whichconnects the storage battery thereto.
 6. The uninterruptible powersupply device according to claim 1, wherein said converter comprises atransducer of alternating and direct current which connects to the powersource in parallel with the load, and which connects the storage batteryand a direct-alternating current inverter.
 7. The uninterruptible powersupply device according to claim 1, wherein said limited dischargecurrent of the storage battery, caused by controlling the output voltageof the converter to lower below the steady state, is almost constant atwhat is equivalent to 10-50% of the maximum current of the load.
 8. Theuninterruptible power supply device according to claim 1, wherein saidcontrol circuit connects to a trigger signal source which comprises amemory in which an operational schedule for the degradation judgment isstored, and the converter starts to lower the output voltage at thetiming of the trigger signal and the storage battery then starts todischarge.
 9. The uninterruptible power supply device according to claim1, wherein said converter and said control circuit comprise a rectifierfor obtaining a direct current from the alternating current powersource, and a closing loop for bringing the voltage of the directcurrent close to an appointed direct current voltage with a pulseduration modulation control for an alternating input voltage of itself.